The Neuroimaging Laboratory of the Clinical Research Center proposes to examine the structural basis of both major and minor depression in elderly subjects with significant medical comorbidity using magnetic resonance imaging (MRI). High intensity signals occurring in the periventricular, deep white matter and subcortical regions of the brain and specific volumetric indices of the brain, cerebrospinal fluid and ventricles will be examined using a 1.5 Tesla GE signa scanner with head coil. Both T2 (TR=2500-3000 msec, TE=80-90 msec) and Proton Density images (TR=2500-3000 msec, TE=17-30 msec) will be analyzed for volumetric measures and for the presence of high intensity signals. The initial studies will assess the relative contribution of subclinical cerebrovascular disease and atrophy in the pathophysiology of late life depression in long term care residents with medical comorbidity and in depression occurring post myocardial infarction. The Laboratory will concurrently develop more sophisticated methods for assessing the volumes of focal brain regions that are relevant to the pathophysiology of depression. In addition to structural approaches, we will develop techniques that use MR scanning to examine physiological changes that occur in the brain. The use of complementary approaches to examine brain function, will help us elucidate some of the underlying mechanisms of late life depression.